How to Programming with Garbage-collection

vb.net,excel,datagridview,garbage-collection,oledb

No, the list reference is still live (and thereby also the references to the integer objects). The JVM will not deduce that the list is half-way traversed and that some Integer objects will not be needed anymore. If you want the objects to be eligible for garbage collection, you'll have...

VB.NET Releasing Excel file after reading so it can be overwritten

After much research and frustration, I found a solution. The connection string of my OleDB connection needs the tidbit added: OLE DB Services = -4 which disables connection pooling. As it happens, the connection is not disposed of (which was the initial hypothesis) when the connection is closed, but instead...

How does copy collector in java manages to skip dead objects from visting?

java,scala,garbage-collection,jvm

I think the confusion is with the definition of "visiting". Initially all objects need to be "visited" and the ones unreachable through strong references put in various internal queues (see weak/soft/phantom references), including the finalizer queue. All throughout this process the object is still considered reachable, and thus not collectable...

A useful metric for determining when the JVM is about to get into memory/GC trouble

One reliable way is to register a notification listener on GC events and check the memory health after all Full GC events. Directly after a full GC event, the memory used is your actual live set of data. If you at that point in time are low on free memory...

Are null and undefined equally valid for explicitly making objects unreachable?

javascript,ios,swift,garbage-collection,javascriptcore

It does not matter what value you assign: it might be null, undefined, {} or 42. What matters is that you need to break the connection between a variable and an object in heap. As soon as an object is not reachable - it's a candidate for being collected, regardless...

JavaScriptCore on iOS: VM Garbage Collector not automatically emtpying

So this was kind of my own problem as I was initializing a new JavaScript VM everytime I called the function from my test. I got around that by initializing one VM at the start of my JSBridge class and voila every call got handled perfectly. But still there seems...

Can I force collection for objects of certain type only?

c#,.net,com,garbage-collection,rcw

No, It's not possible, you can only force a garbage collector to run but you can not force it to work according to your logic. For more information on garbage collector please read this: https://msdn.microsoft.com/en-us/library/ee787088(v=vs.110).aspx Also GC is a static class, we can't override any of it's method :(...

Garbage Collection invalidates FileDescriptor?

android,garbage-collection,file-descriptor

You aren't retaining a reference to the AssetFileDescriptor created by openFd(). When it gets GC'ed, it has an internal ParcelFileDescriptor that is also eventually GC'ed. That, in turn, has the reference to the FileDescriptor that you are retrieving in the call to getFileDescriptor(). It also happens to have a finalize()...

Creating and returning object from function: can this avoid garbage collection?

javascript,object,scope,garbage-collection,return-by-reference

It (the execution context) will be eligible for garbage collection. (The function object itself will be kept alive of whoever called it to begin with, until that object dies - but it will not be kept alive by the returned 'newObj'.) Just because a reference to the object is stored...

G1GC Strange behavior

java,garbage-collection,g1gc

You are suffering from System.gc() calls as can be seen in your log: 2015-06-14T14:56:23.682+0300: 12790,173: [Full GC (System.gc()) 121M->118M(1024M), 0,4524898 secs] [Eden: 4096,0K(561,0M)->0,0B(561,0M) Survivors: 0,0B->0,0B Heap: 121,7M(1024,0M)->118,2M(1024,0M)], [Metaspace: 135216K->135216K(1177600K)] [Times: user=0,71 sys=0,00, real=0,45 secs] 2015-06-14T14:57:23.682+0300: 12850,174: [Full GC (System.gc()) 121M->118M(1024M), 0,4732930 secs] [Eden: 3072,0K(561,0M)->0,0B(561,0M) Survivors: 0,0B->0,0B Heap:...

Using “this” in a callback vs external variable and the garbage collector

java,garbage-collection,jvm,g1gc

This advice looks weird: the object the req variable refers to (the same the this would refer to) as well as the anonymous function objects (which are hold by onsuccess, onerror and onupgradeneeded properties) would all be garbage collectible simultaneously as soon as the query has completed and callbacks have...

JVM is functioning very differently with same flags

I would expect than better PC would have much better results but now I don't even know which one is better... Better is subjective. Depending on whether you need throughput (fraction of CPU cycles spent GCing), sustainable allocation rates, low pause times or low footprint. Generally there's a tradeoff...

Create variable or call method few times - What's better?

c#,variables,methods,garbage-collection

In general, when you need to use the result of a method call multiple times, you should assign it to a local variable first. The local variable would only require your method's stack frame to be a few bytes larger (8 bytes for an object variable on 64-bit), and would...

Why aren't the earlier terms here being garbage-collected?

haskell,memory,garbage-collection,ghc,compiler-optimization

Let's compare actual numbers. Your version of kolakoski uses about 70k if run without optimization: $ ghc --make Kolakoski-Unit && ./Kolakoski-Unit +RTS -s 2 288,002,359,096 bytes allocated in the heap 1,343,933,816 bytes copied during GC 67,576 bytes maximum residency (422 sample(s)) 52,128 bytes maximum slop 2 MB total memory in...

JVM ClassUnloadingWithConcurrentMark flag

java,garbage-collection,jvm,g1gc

I'm afraid that If I'll use this option I'll have even more problems Why don't you just setup a test environment for these kinds of things and test it yourself? Anyway, as already answered over here, the VM will perform some last-ditch heroics (1-2 full GCs, complete soft reference...

What to look for when parallelized code runs faster in Visual Studio automated tests?

c#,multithreading,visual-studio-2010,visual-studio,garbage-collection

I finally found a solution to our problem. Setting up an App.config file with gcServer set to true solved our problem. Our application is so instantiation heavy that the garbage collector was killing performance. I guess Visual Studio works its garbage collector differently when running unit tests? In the future...

Clear memory after some number of records passed

ruby-on-rails,ruby,garbage-collection,sidekiq

You should always use find_each when dealing with potentially large tables. That way, models will be retrieved from the database and loaded in memory batch by batch (the default size is 1000 but you can customize it to your needs). Just be aware that sorting by arbitrary columns doesn't play...

Does GCHandle.Alloc allocate memory?

c#,multithreading,garbage-collection,threadpool

Everything is open source today, you can have a look and find out for yourself. If you dig into GCHandle.Alloc, you'll see the it calls a native method called InternalAlloc: [System.Security.SecurityCritical] // auto-generated [MethodImplAttribute(MethodImplOptions.InternalCall)] [ResourceExposure(ResourceScope.None)] internal static extern IntPtr InternalAlloc(Object value, GCHandleType type); Drilling down into the CLR code, you...

Memory leak in MediaPlayer

My guess is that the Thread objects created aren't garbage collected in time. As you are stating in your comment that you are out of luck with respect to finding a solution that doesn't involve a memory leak, I'm posting this alternative as an answer even though it doesn't attempt...

How do I terminate a task upon object deletion? c#

c#,garbage-collection,task

The function I needed was ~Melody(). It doesn't have to be called manually, unlike Dispose(). Thanks to Denis Yarkovoy...

Know what objects got garbage collected

java,garbage-collection,g1gc

You can use JVisualVM from your JDK to analyze memory usage. You should open your application and take a memory dump, you'll see how much memory is allocated by different classes. It can point you to right directions....

What causes long spin and sync times in Java?

The problem here is that it takes your application a long time to reach a safepoint. The Stopping threads output denotes the time it takes between the JVM issues a safepoint request until all threads have reached a safepoint. The sync value shows same thing - it is the time...

Dispose/finalize pattern : disposing managed ressources

c#,garbage-collection,dispose,finalize

My question is : How can I free the attributes of Base in the Dispose method ? (_String, classe1, foo) You don't need to, that's the job of the garbage collector. Implementing IDisposable is a way for the framework to let you release any unmanaged resources you have allocated,...

Garbage Collector doesn't immediately collect finished thread [duplicate]

java,multithreading,memory-management,garbage-collection

Could it be that you are asking the wrong question? What I mean: is the fact that garbage collection is not happening "immediately" a problem for you? I am pretty sure - when you start another such thread that needs a lot of memory, the GC will kick in all...

How is garbage collection triggered in JavaScript?

javascript,memory-management,garbage-collection

There are many ways GCs can be triggered allocation-triggering: there is no more room in the allocation buffers/young generation/howeveritiscalled and a GC is required to free up objectsThis gets a bit more complicated in a mixed GC/manual allocation environment. malloc wrappers might need to trigger GCs too since javascript can...

Does /usr/bin/time include post program garbage collection for a java program?

java,linux,time,garbage-collection

As a general rule the Java Runtime Environment doesn't perform garbage collection on exit. Of more immediate concern would be the performance costs of JIT and of course trying to Write Dumb Code. Also, the signature of main() takes a String[] like public static void main(String[] args) { ...

Windows task manager javaw.exe memory vs Java Mission Control

java,memory,garbage-collection

When the JVM starts up, it allocates a continuous region of memory for the heap. This memory can be turned into real memory lazily but almost never is passed back to the operating system. The heap is but one region of memory the JVM uses. It may be the most...

How to prevent module from deleting by garbage collector or reimport it inside del method

python,garbage-collection

You can bind a reference to the os.unlink() function as default argument, so you still have access to just the function when the hook runs: def __del__(self, _os_unlink=os.unlink): if self.config_object.logfile is not None: import os try: _os_unlink(self.config_object.logfile) except (WindowsError, AttributeError): pass However, take into account that there is never a...

JavaScript/JQuery Garbage Collection and Events

javascript,jquery,html,dom,garbage-collection

You should not worry about memory leaks if you remove element with dedicated methods like remove, replaceWith, html, etc. Those methods jQuery calles $.cleanData method. For example, for replaceWith you can see that jQuery removes events and data objects from internal cache in order to prevent leaks: if ( jQuery.inArray(...

WPF ViewModel GC

c#,wpf,mvvm,memory-leaks,garbage-collection

Actually you do have dependency injection right now, since you are injecting the viewmodel into the dialog via constructor. While the dialog view is running, it contains a reference to dialogViewModel in MainViewModel. When you close the dialog, the control is given back to the OnModelRaisedEvent method, and immediately after...

Drop reference when only a single link to it

c#,reference,garbage-collection

The best choice would be just .Clear() the dictionary when the UI becames invisible

Static variables in POJO and garbage collection of objects and classes

java,garbage-collection,static-members

No, the static field will not prevent garbage collection of your subclasses (if it did, this would be a major problem, making static fields almost unusable in a garbage-collected language!) You can test this by adding a finalizer to your classes, then create a bunch of them in a loop,...

Which has better garbage collection, MRI 2.2 or Rubinius 2.5.3

ruby,garbage-collection,rubinius

It seems that Rubinius does not garbage collect symbols, see this issue. Is this still the case and is GC-ing symbols a big improvement? Rubinius currently doesn't garbage collect Symbols. We'll add this eventually but for now there are more pressing matters to take care of (e.g. support for...

How to list all object in GC finalization list?

c#,garbage-collection,finalization

I do not think that there is a way to get at the finalization queue via .NET's managed Framework Class Library (FCL). I suspect that if you want to do this programmatically instead of debugging with WinDbg, you (just like WinDbg and similar tools) will need to use the CLR's...

Android - Javascript Interface with pointer to WebView - how to achive it without memleak

java,javascript,android,webview,garbage-collection

WebView will hold your object (the instance of JSInterface) until you call removeJavascriptInterface("appBridge") and reload your page. But this kind of a circular reference isn't actually a problem for a mark-compact collector (used in languages with built-in garbage collection, like Java or JavaScript), because once such looped construction doesn't have...

Why JVM is designed in a way that it does not allow force Garbage Collection? [closed]

javascript,node.js,garbage-collection,v8

Forcing garbage collection is inefficient, and unnecessary in most cases1 ... if you have written your program correctly. Reference: Why is it bad practice to call System.gc()? It turns out that if you control the launching of the JVM that will run your application (or applet or servlet or whatever)...

Unclear about V8 Garbage Collection

Both shirt (1, 2) and callback (3) are referenced by inner functions. Thus their bindings have to be heap-allocated, and will only become garbage when all those inner functions have become garbage. In this example, that will happen after async.series has finished execution and dropped its reference to the array...

Prevent object from getting garbage collected

no, the GC won't collect the TaskTimerObject. the field TaskTimer is a Root Referance which points to TaskTimerObject....

GC behavior when assigning null to reference variable

I suspect it's due to definite assignment. If you assign a value to holdLastObject before the loop, it's definitely assigned for the whole method (from the point of declaration onwards) - so even though you don't access it after the loop, the GC understands that you could have written code...

Javascript - free a memorized function

You are unbinding the event handler, then immediately reapplying the same event handler to the same element. You need to re-organise your code so that you bind the event handler to the new element as you create the new row http://jsfiddle.net/2fLrsjcz/ var currentTable = $('table'); function bindKeyDown(lastEditable) { lastEditable.keydown(function(e) {...

Why WeakReference to a WeakRef object is not garbage collected?

GC will not delete WeakReference itself, it will delete only the object it references, so map will still contain the WeakReference. What you should check is weakReference.get(). This should return null after gc(). Just in case, make a Thread.sleep(1000) before check, so that GC has some time to do its...

Effect of setting -XX:+PerfDisableSharedMem JVM flag to false

java,performance,garbage-collection,g1gc

Then /tmp/hsperfdata* won't be written. Which, according to hotspot-runtime-dev discussions, will prevent some performance monitoring command line tools from automatically discovering running VMs automagically. They can still attach to the running process if the PID is specified explicitly.

Does allocation performance degrade on a large number of live instances when using G1?

As discussed in the comments above: Your test-case does pre-allocate very large reference arrays that are long-lived and essentially occupy a region of their own (they probably end up in the old gen or humongous regions) and then populating them with millions of additional objects that are likely to live...

Will Application pause during minor GC in java?

Will the whole application stop serving the requests during Minor GC execution? Yes, AFAIK every collector (apart from some commercial, expensive implementations perhaps) will stop the world for GC collection. It won't necessarily stop the world for the entirety of its pass, but it will contain a stop the...

.NET GC deleting object in use

java,multithreading,garbage-collection

Surely, this can't be really happening and I must be doing something wrong. Nope, it can absolutely be happening (this is why writing finalizers is hard, and you should avoid them where you can, and be very careful when forced to write them). An object can be GC-ed as...

Why does restricting GC to 1 thread increase performance?

I am not an expert on garbage collectors, so this is probably not the answer you'd like to get, but maybe my findings on your issue are interesting nevertheless. First of all, I've changed your code into an JUnit test case. Then I've added the JUnitBenchmarks extension from Carrot Search...

Timer does not get garbage collected [duplicate]

c#,timer,garbage-collection

if a class contains a member that is disposable that class should implement IDisposable as well Note: BTimer needs to implement IDisposable. class Cellules : IDisposable { BTimer timer // disposable member public void Dispose() // implementing IDisposable { timer.Dispose(); } } then of course when you are done call...

What happens to unused return values?

java,garbage-collection,return-value

The compiler sees that it is not used and just leaves the value on the (return) stack unassigned aka removes it. If you assign it but not use it, it lives until this references is not longer in use. See the attached screenshot. Eclipse and a bytecode plugin. Under L0,...

Exposing whether an application is undergoing GC via UDP

node.js,memory-management,garbage-collection,v8

There are a whole bunch of ways to monitor and report on a VM remotely. A well-known protocol, for example, is SNMP. But this is a very complicated subject. Implementation sort of depends on your requirements. If you need to be really sure a VM is in a good state,...

nodejs decrease v8 garbage collector memory usage

You need to control the max memory size flags (all sizes are taken in MB). The recommended amounts for a "low memory device" are: node --max-executable-size=96 --max-old-space-size=128 --max-semi-space-size=1 app.js for 32-bit and/or Android and node --max-executable-size=192 --max-old-space-size=256 --max-semi-space-size=2 app.js for 64-bit non-android. These would limit the heap totals to 225mb...

Why remark phase is needed on concurrent GC

java,concurrency,garbage-collection

And modified pointer to another object is not a problem in fact. Because Dead object can not revive They really can't but do you know which objects are dead? No! Why? You don't know it after the initial mark phase as you look only at the thread stacks and...

Counting total objects queued for garbage collection

java,memory-leaks,garbage-collection,websphere

(Question title:) "Counting total objects queued for garbage collection" (From the question's body:) "My problem, however, is that I can't seem to find a way to count the total objects currently alive in the various generations." Remark: Your question's title and body ask for opposite things. In the title,...

WebSphere 7 - Can excessive Garbage Collection lead to out of memory?

The error message you get indicate a problem with native memory, that is, memory outside the heap. The garbage collector is not responsible for off-the-heap memory, why you can not affect this error with garbage collector settings. Excessive garbage collecting should not lead to native memory issues (unless there is...

how does the mark (in mark-and-sweep) function trace out the set of objects accessible from the roots?

c++,c,garbage-collection

There's usually a root set, not just a single root object. The root set is basically all global variables, and all currently active local variables (e.g., all locals that are currently on the stack). One of the real difficulties with adding garbage collection to C or C++ is the possibility...

How to delete a thread in Java

java,multithreading,garbage-collection

It looks like your Client class is either extending from Thread or implementing Runnable. Either ways, your Client class is running an infinite while(true) loop. Unless this loop exits, the Client class won't be garbage collected. Therefore, you need to break out of the while(true) loop. while (true) { try{...

PHP Garbage collection when nullifying

php,garbage-collection

You will only ever modify the variable inside the function. Your Bob instance will continue to exist, because variables outside the function are still referencing it. Bob won't get garbage collected until all references to it are gone/have become inaccessible. An object instance exists somewhere in a pool of object...

delete ref to object in array javascript

javascript,memory-leaks,garbage-collection,google-chrome-devtools

I recommend taking a look at Deleting Objects in JavaScript, When should I use delete vs setting elements to null in JavaScript? and Memory Management (nice reference, @Karthick). Since Javascript is garbage collected, you don't need to delete objects themselves - they will be removed when there is no way...

DOM nodes not garbage collected

Per your request, adding this as an asnwer. Have you looked at more details on any of these DOM elements to see which DOM elements they are and perhaps that gives you a clue as to what code would have ever referenced them. One source of references that trips some...

No evacuation failures but still FullGC in G1GC

java,garbage-collection,g1gc

It's likely not a good idea to run G1GC on java 7. Back then it had a lot of problematic behaviors. Among them that class unloading needed a full GC, this has been fixed with jdk8u40 Not to mention that GC logs give more useful information in 8. Other causes...

Rotating bitmap in main game loop without overloading GC in Android

java,android,bitmap,garbage-collection

Some think like this: Bitmap image; Matrix m; . . . public YourClass(){ m = new Matrix(); image = Bitmap.createBitmap(image, 0, 0, width, height,); } . . . public void mainGameLoop(Canvas c){ m.setRotate(angle, imageCenterX, imageCenterY); yourCanvas.drawBitmap(image, m, null); } ...

How local variable usage infomation is maintained in .net clr source code

.net,garbage-collection,clr,jit

Disclaimer: I'm no expert on the CLR or RyuJIT. I may be completely wrong about all of this. I came across the following section in the RyuJIT chapter of the Book of the Runtime: For lvlVars with tracked lifetimes, or for expression involving GC references, we report the range over...

Potential causes of memory leaks in Android

java,android,memory-leaks,garbage-collection

Is there anything else that I should watch that may cause a noticeable memory leak? Declaring a member field static almost guarantees a memory leak. Anonymous classes that last beyond the lifetime of the parent class, such as Volley Requests, also produce memory leaks, because they hold an implicit...

C# Garbage Collector Begin/End Callback [duplicate]

c#,callback,garbage-collection

You can't get notification directly in manged code because managed code is suspended (or at least not guaranteed to run your thread in case of background GC) during GC. Options: You can get approximate notification with GC.RegisterForFullGCNotification as shown in Garbage Collection Notifications article. You can watch performance counters related...

Garbage collection methods in c# application

c#,.net,memory-management,garbage-collection

The KeepAlive will only delay the finalizer being called on a class (by making the object live longer and not having it be eligible for finalization) and CancelFullGCNotification has nothing to do with finalizing. Only SuppressFinialize will prevent the finalizer from running on a class....

How to disable BufferRecycler?

java,garbage-collection,jackson

Actually something new that may be relevant here: Jackson 2.6 does have a new JsonFactory.Feature, USE_THREAD_LOCAL_FOR_BUFFER_RECYCLING: disabling of which will prevent reuse of BufferRecycler. You could maybe try 2.6.0-SNAPSHOT with this option to see the difference.

G1 young GC does not free memory - to-space exhausted

c#,garbage-collection,task-parallel-library

You are suffering from evacuation failures as can be seen by the to-space exhausted part of the start message for the collection. This occurrs when there is not enough free space on your heap to promote survived or promoted objects (or both) and the heap can not be expanded more....

Can a call to Task.GetAwaiter().OnCompleted() fail because of garbage collection?

In short, after appreciation of all the answers and comments, my realization about using GetAwaiter() is: don't do it. If you need it, this is most likely an indication that your asynchronous design is in badly need of refactoring....

GC cleaning the object before calling onPictureTaken method

android,garbage-collection,picturecallback

I figured out that problem is my method (takePicture), which was being closed before the onPictureTaken was called. I solved the problem putting a delay into the takePhoto method.

-XX:+PrintTenuringDistribution doesn't print size per age

java,garbage-collection,metaspace

According to this blog post it's working as intended. Well, this is the expected behavior and is not a bug. Throughput collector does not use the age table like the other collectors do. And due to that reason, the age histogram information is not printed with the throughput collector. With...

Java 8 Metaspace - Avoid decrease

Setting MaxMetaspaceFreeRatio=100 should prevent it from shrinking

Are Configuration.ConfigurationSettings.AppSettings values interned strings?

c#,string,garbage-collection,runtime

No. Configuration strings are regular strings and constructed at run-time - configuration files are not compiled into assemblies, so will not be interned by compiler. Note that in general the fact that string is not coming from compiled source says nothing about whether such strings are interned or not as...

Will .Net call Dispose for me in this case?

.net,f#,garbage-collection,idisposable

Here's everything you'll need to know about IDisposable: CLR Inside Out: Digging into IDisposable In short, Dispose will not be called by the Garbage Collector, but if the object has a finalizer, the finalizer will be called. All well-designed implementations of IDisposable that hold unmanaged resources will have a finalizer...

Garbage Collection and Using - Why is memory not released after `using{}` block?

c#,.net,garbage-collection,using

Disposing of objects has nothing to do with garbage collection. Garbage collection has to do with cleaning up of managed resources. Disposal is there to clean up unmanaged resources that the GC isn't tracking. Sometimes those unmanaged resources are memory allocated explicitly without going through the GC, sometimes they're locks...

What is the best way to clear a BST for garbage collection?

java,garbage-collection,binary-search-tree

Any object that cannot be reached by any live thread will be eligible for garbage collection. Based on that: Yes. No. Depends on the implementation of GC. Anyway, as a Java programmer, you can't control it. All you can do is have a trust that it will do its job...

c# Check Garbage Collection [duplicate]

Is there any way to check what classes are collected by GC and what are not? No, because to check on an object you'd still need a reference to it and that would prevent its collection. You can build an administration with WeakReferences but that would be awkward and...

How GC suspends/blocks the application threads